(aa,b) (ba,a) (bc,a) (c,start) (d,) (b,finish) (,)

Example program from the PROLAN/M documentation. If you run it with the 
input string "abcabcd", the result is "finish", going through the 
following steps:

abcabcd
aaabcd
babcd
abcd
aad
bd
b
finish
